Viruses evolve in response to what component of the human immune system listed below?

There are 500 toads in the population. Within this population, coloration is determined by one gene with two alleles, a brown allele (B) and a yellow allele (b). The brown allele is dominant to the yellow allele. There are 350 toads that are brown. Assume the population is in Hardy-Weinberg equilibrium. Given this information, the frequency of the b allele is approximately and you would expect toads to be heterozygous (Bb).  

Two species of fruit fly found on the island of Melanesia are morphologically indistinguishable.  The two species share habitats but rarely interbreed in the wild. Males of both species court females from both species, but the females have a strong preference for the courting display of males of their own species. Based on this information, fruit fly courtship would be considered a form of , which occurs .

Identical (monozygotic) twins were adopted by different families at birth and were raised in different parts of the country. However, both twins grow up to have perfect pitch. This would suggest what about the shared musical talent of these twins?

Which of the following was not involved in the evolution of multicellular organisms from single-celled protists?

This phylogenetic tree depicts the evolutionary relationships of eight major vertebrate classes.  Tiktaalik is an intermediate fossil that represents an early ancestor of all tetrapods. Specifically, Tiktaalik is known for its wrist, a key feature of the tetrapod limb that made it possible for which major evolutionary transition in animals? If you were to add Tiktaalik to this phylogeny, where would the Tiktaalik branch extend from?

Florida panthers have been the target of major conservation efforts over the last few decades. Due to increasing development and habitat loss, their population has become fragmented into small reserves. This has resulted in these small, isolated populations becoming severely inbred. How does inbreeding threaten a population’s health? To counter the effects of habitat fragmentation, conservation biologists are developing corridors to allow individuals to move between these isolated populations. These corridors will promote , which will increase genetic variation and reduce inbreeding.

Roundworms are able to reproduce sexually or asexually. The graph below shows the results of an experiment that compared sexual reproduction rates in roundworm populations exposed to three different bacteria treatments: roundworm populations that were never exposed to bacteria (dotted black line) roundworm populations that were periodically exposed to bacteria that were allowed to evolve (solid black line) roundworm populations there were periodically exposed to bacteria that were not allowed to evolve (highlighted in red). In Treatment 3, the rate of sexual reproduction increased, but then, after 8 generations, decreased. What is the most likely cause of this decrease in sexual reproduction?

CHOOSE THE BEST ANSWERS In a population of cows, a single gene controls hair type. The curly hair allele (H) shows incomplete dominance with the straight hair allele (h). The hair of heterozygous individuals (Hh) is wavy. Another gene controls coat color. The red (R) and white (r) alleles are co-dominant. The coloring of heterozygous individuals (Rr) is called roan . After breeding a wavy, roan bull with several wavy, roan females, you observed the following phenotypic ratio in the offspring: 8 curly, red : 16 wavy, roan :  7 straight, white Part 1: Based on this observed ratio,  are the two genes linked?  Part 2:  If they are linked, how are the two genes’ alleles linked?   

Which of the following mechanisms would result in lower genetic diversity within a population?